In my universe, Scar is not the son of Uru and Ahadi, but rather the son of Ahadi and Uru's sister, Nakato. He was born before Mufasa.
However, Uru was never happy about Nakato loving Ahadi, and made her sister give up Scar in exchange for not exiling her.
Despite that, Uru never grows to love Scar. She favors her own sons, Mufasa and Mega, over him, and despite him being the oldest, he won't be the leader of the Pridelands. She doesn't go out of her way to physically abuse him, but often she diminishes his worth by comparing him to Mufasa, which is where his jealous towards his brother stems from.